How to select overlapping objects
If multiple objects are very close together or even overlapping entirely and visually indistinguishable from one another, you can use Alt + right click to get a drop-down menu that allows you to choose from a list of objects in that area.

In the screen shot below there are actually two identical cubes overlapping. The menu lets us choose which one to select.



More on this and other selection methods in the Blender Reference Manual.